Measurement system capable of adjusting AOI, AOI spread and azimuth of incident light

Abstract

A measurement system is disclosed. A measurement system includes an illumination module, a mirror module, a stage, and a detector. The illumination module includes a light source, an optical fiber, a collimating mirror, a polarization state generator, a beam control mirror, and a relay mirror. The mirror module includes a first beam splitter and a reflective objective mirror. The beam control mirror is movable to relay light received from the polarization state generator to various positions on the relay mirror.

What is claimed is: 
     
       1. A measurement system comprising:
 an illumination module comprising a light source, an optical fiber, a collimating mirror, a polarization state generator, a beam control mirror, and a concave relay mirror; 
 a mirror module comprising a first beam splitter and a reflective objective mirror; 
 a stage; and 
 a detector, 
 wherein the optical fiber includes a core having a diameter that sets an angle-of-incidence spread of light received from the light source, and relays the light to the collimating mirror, 
 wherein the concave relay mirror reflects light received from the beam control mirror onto the mirror module and the beam control mirror is movable to relay light received from the polarization state generator to a plurality of positions on the concave relay mirror, such that the beam control mirror and the concave relay mirror in combination adjust an angle of incidence of the light onto the stage, and 
 wherein the reflective objective mirror comprises a convex mirror and a concave mirror having an opening formed at a center of the concave mirror and, when viewed in a top view, the concave mirror has a disc shape and the convex mirror has a circular shape, such that the beam control mirror, the concave relay mirror, the convex mirror and the concave mirror in combination adjust an azimuth of the light incident upon the stage from the mirror module. 
 
     
     
       2. The measurement system according to  claim 1 , wherein the collimating mirror converts light received from the light source into straight light, and provides the straight light to the polarization state generator. 
     
     
       3. The measurement system according to  claim 1 , wherein the beam control mirror and the concave relay mirror in combination converts straight light into focal light. 
     
     
       4. The measurement system according to  claim 1 , wherein the beam control mirror comprises a flat mirror which is swingable or semi-rotatable. 
     
     
       5. The measurement system according to  claim 1 , wherein the beam control mirror comprises a concave mirror which is movable in forward and rearward directions, left and right directions, and upward and downward directions. 
     
     
       6. The measurement system according to  claim 1 , wherein:
 the polarization state generator comprises a polarizer and a compensator; 
 the polarizer primarily polarizes the light received from the collimating mirror to convert the light into linearly polarized light; and 
 the compensator secondarily polarizes the linearly polarized light to convert the linearly polarized light into elliptically polarized light. 
 
     
     
       7. The measurement system according to  claim 1 , wherein:
 the illumination module further comprises a transparent swing panel between the polarization state generator and the beam control mirror; and 
 the transparent swing panel provides light provided from the polarization state generator to various positions on the beam control mirror. 
 
     
     
       8. The measurement system according to  claim 1 ,
 wherein the convex mirror is disposed at a lower side of the concave mirror in a direction of incidence of light from the first beam splitter and is upwardly convex, and the concave mirror is disposed at an upper side of the convex mirror and is downwardly concave. 
 
     
     
       9. The measurement system according to  claim 8 , wherein:
 a first half portion of the convex mirror receives light passing through the opening of the concave mirror, and reflects the received light onto a first half portion of the concave mirror; 
 the first half portion of the concave mirror provides, onto the stage, the light reflected from the first half portion of the convex mirror; 
 a second half portion of the concave mirror receives light reflected from the stage, and reflects the received light to a second half portion of the convex mirror; and 
 the second half portion of the convex mirror reflects the light reflected from the second half portion of the concave mirror such that the light is outwardly reflected through the opening. 
 
     
     
       10. The measurement system according to  claim 1 , wherein:
 the measurement system further comprises a pupil analyzer including a second beam splitter, a monitoring relay mirror, and a monitoring camera, and 
 the second beam splitter is disposed in an optical path between the mirror module and the detector. 
 
     
     
       11. The measurement system according to  claim 1 , wherein:
 the detector comprises a polarization state analyzer, an imaging mirror, and an imaging camera; and 
 the polarization state analyzer comprises a polarizer and a compensator. 
 
     
     
       12. The measurement system according to  claim 1 , wherein a first optical path from the light source to the stage includes, in order, the optical fiber, the collimating mirror, the polarization state generator, the beam control mirror, the concave relay mirror, the first beam splitter, and the reflective objective mirror, and
 wherein a second optical path from the stage to the detector includes, in order, the reflective objective mirror and the first beam splitter. 
 
     
     
       13. A measurement system comprising:
 an illumination module comprising a light source, an optical fiber, a collimating mirror, a polarization state generator, a beam control mirror, and a concave relay mirror; 
 a mirror module comprising a beam splitter and a reflective objective mirror; 
 a stage; and 
 a detector, 
 wherein the light source generates light, and provides the light to the collimating mirror via the optical fiber, 
 the optical fiber includes a core having a diameter that sets an angle-of-incidence spread of light received from the light source, and relays the light to the collimating mirror, 
 the collimating mirror converts the light received from the light source into straight light, and provides the straight light to the polarization state generator, 
 the polarization state generator polarizes the straight light received from the collimating mirror, and provides the polarized light to the beam control mirror, 
 the concave relay mirror reflects light received from the beam control mirror onto the mirror module and the beam control mirror is movable to relay the polarized light received from the polarization state generator to a plurality of positions on the concave relay mirror, such that 
 the beam control mirror and the concave relay mirror in combination convert the polarized light received from the polarization state generator into focal light, provide the focal light to the mirror module to adjust an angle of incidence of the focal light onto the stage, and 
 the reflective objective mirror comprises a convex mirror and a concave mirror having an opening formed at a center of the concave mirror and, when viewed in a top view, the concave mirror has a disc shape and the convex mirror has a circular shape, such that the beam control mirror, the concave relay mirror, the convex mirror and the concave mirror in combination adjust an azimuth of the light incident upon the stage from the mirror module. 
 
     
     
       14. The measurement system according to  claim 13 , wherein the reflective objective mirror and the stage are movable to adjust the angle of incidence and an azimuth of light incident upon the stage from the mirror module. 
     
     
       15. The measurement system according to  claim 13 ,
 wherein a first optical path from the light source to the stage includes, in order, the optical fiber, the collimating mirror, the polarization state generator, the beam control mirror, the concave relay mirror, the beam splitter, and the reflective objective mirror, and 
 wherein a second optical path from the stage to the detector includes, in order, the reflective objective mirror and the beam splitter. 
 
     
     
       16. A measurement system comprising:
 an illumination module comprising a light source, an optical fiber, a collimating mirror, a polarization state generator, a beam control mirror, and a concave relay mirror; 
 a mirror module comprising a beam splitter and a reflective objective mirror, the reflective objective mirror comprising a convex mirror and a concave mirror and the convex mirror is below the concave mirror in a direction of incidence of light from the beam splitter and, when viewed in a top view, the concave mirror has a disc shape and the convex mirror has a circular shape; 
 a stage; and 
 a detector, 
 wherein the light source generates light, and provides the light to the optical fiber, 
 the optical fiber includes a core having a diameter that sets an angle-of-incidence spread of the light, and the optical fiber provides the light to the collimating mirror, 
 the collimating mirror converts the light into straight light, and provides the straight light to the polarization state generator, 
 the polarization state generator polarizes the straight light received from the collimating mirror, and provides the polarized light to the beam control mirror, 
 the concave relay mirror reflects light received from the beam control mirror onto the mirror module, 
 the beam control mirror is movable to relay the polarized light to the concave relay mirror to a plurality of positions on the concave relay mirror such that 
 the beam control mirror and the concave relay mirror in combination convert the polarized light into focal light, and provide the focal light to the beam splitter of the mirror module; to adjust an angle of incidence of the focal light onto the stage, 
 the beam splitter provides the light received from the illumination module to the reflective objective mirror, such that the beam control mirror, the concave relay mirror, the convex mirror and the concave mirror in combination adjust an azimuth of the light incident upon the stage from the mirror module, 
 a first half portion of the convex mirror and a first half portion of the concave mirror exclusively provide light received from the illumination module to the stage, and 
 a second half portion of the convex mirror and a second half portion of the concave mirror exclusively reflect, onto the detector, light reflected from the stage. 
 
     
     
       17. The measurement system according to  claim 16 ,
 wherein a first optical path from the light source to the stage includes, in order, the optical fiber, the collimating mirror, the polarization state generator, the beam control mirror, the concave relay mirror, the beam splitter, the first half portion of the convex mirror and the first half portion of the concave mirror, and 
 wherein a second optical path from the stage to the detector includes, in order, the second half portion of the convex mirror and the second half portion of the concave mirror and the beam splitter.